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Rain now lowers Flying-Type/Levitating Pokemon's Speed by half
Every type gets their own type-based equivalent of Stealth Rocks. Every one of these hazards can stack with eachother + Spikes/Toxic Spikes/Sticky Web/ect
Intimidate lowers Attack, Special Attack and Speed
Steel now resists every type, imcluding types which previously did supereffective damage towards it
Hail now does damage to Ice-Types